| commit | 0c4f345fe9ab0a54de5076661bba086250c41662 | |
| author | Mark Williams <mwilliams@fb.com> | |
| Fri, 17 Mar 2017 13:24:45 +0000 (17 06:24 -0700) | ||
| committer | Hhvm Bot <hhvm-bot@users.noreply.github.com> | |
| Fri, 17 Mar 2017 13:48:05 +0000 (17 06:48 -0700) | ||
| tree | d53cde018e8241366ae4825a32f5d5f6320dfb14 | treesnapshot (tar.gz zip) |
| parent | aeaa6041f9d682f0cc6c576492609a9eb80215b2 | commitdiff |
Take advantage of equivLocals and static locals
Summary:
Dce often cares whether dropping a reference might run a
destructor. If we know that a stack slot has the same contents as a
local, that can't happen. Similarly if two locals have the same
contents, it can't happen. In addition, unsetting a static local won't
have side effects, because the static itself still refers to the ref.
Similarly, assigning a non-ref local to itself is always a no-op.
In addition, I modified the local equivalence tracking to maintain
equivalence sets to get more complete results.
Reviewed By: ricklavoie
Differential Revision: D4716282
fbshipit-source-id: 8cd977c4f5823dd33b9a6fba3e9581a279a40b57
Summary:
Dce often cares whether dropping a reference might run a
destructor. If we know that a stack slot has the same contents as a
local, that can't happen. Similarly if two locals have the same
contents, it can't happen. In addition, unsetting a static local won't
have side effects, because the static itself still refers to the ref.
Similarly, assigning a non-ref local to itself is always a no-op.
In addition, I modified the local equivalence tracking to maintain
equivalence sets to get more complete results.
Reviewed By: ricklavoie
Differential Revision: D4716282
fbshipit-source-id: 8cd977c4f5823dd33b9a6fba3e9581a279a40b57